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Commit 5821bd8c authored by Alex Elder's avatar Alex Elder Committed by Sage Weil
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libceph: small changes to messenger.c 



This patch gathers a few small changes in "net/ceph/messenger.c":
  out_msg_pos_next()
    - small logic change that mostly affects indentation
  write_partial_msg_pages().
    - use a local variable trail_off to represent the offset into
      a message of the trail portion of the data (if present)
    - once we are in the trail portion we will always be there, so we
      don't always need to check against our data position
    - avoid computing len twice after we've reached the trail
    - get rid of the variable tmpcrc, which is not needed
    - trail_off and trail_len never change so mark them const
    - update some comments
  read_partial_message_bio()
    - bio_iovec_idx() will never return an error, so don't bother
      checking for it

Signed-off-by: default avatarAlex Elder <elder@inktank.com>
Reviewed-by: default avatarSage Weil <sage@inktank.com>
parent 7593af92

net/ceph/messenger.c

+31 −32
Original line number Diff line number Diff line
@@ -907,7 +907,10 @@ static void out_msg_pos_next(struct ceph_connection *con, struct page *page, 


	con->out_msg_pos.data_pos += sent;

	con->out_msg_pos.page_pos += sent;

	if (sent == len) {

	if (sent < len)

		return;



	BUG_ON(sent != len);

	con->out_msg_pos.page_pos = 0;

	con->out_msg_pos.page++;

	con->out_msg_pos.did_page_crc = false;
@@ -922,7 +925,6 @@ static void out_msg_pos_next(struct ceph_connection *con, struct page *page, 
		iter_bio_next(&msg->bio_iter, &msg->bio_seg);

#endif

}

}



/*

 * Write as much message data payload as we can.  If we finish, queue
@@ -940,30 +942,31 @@ static int write_partial_msg_pages(struct ceph_connection *con) 
	int ret;

	int total_max_write;

	bool in_trail = false;

	size_t trail_len = (msg->trail ? msg->trail->length : 0);

	const size_t trail_len = (msg->trail ? msg->trail->length : 0);

	const size_t trail_off = data_len - trail_len;



	dout("write_partial_msg_pages %p msg %p page %d/%d offset %d\n",

	     con, msg, con->out_msg_pos.page, msg->nr_pages,

	     con->out_msg_pos.page_pos);



	/*

	 * Iterate through each page that contains data to be

	 * written, and send as much as possible for each.

	 *

	 * If we are calculating the data crc (the default), we will

	 * need to map the page.  If we have no pages, they have

	 * been revoked, so use the zero page.

	 */

	while (data_len > con->out_msg_pos.data_pos) {

		struct page *page = NULL;

		int max_write = PAGE_SIZE;

		int bio_offset = 0;



		total_max_write = data_len - trail_len -

			con->out_msg_pos.data_pos;



		/*

		 * if we are calculating the data crc (the default), we need

		 * to map the page.  if our pages[] has been revoked, use the

		 * zero page.

		 */



		/* have we reached the trail part of the data? */

		if (con->out_msg_pos.data_pos >= data_len - trail_len) {

			in_trail = true;

		in_trail = in_trail || con->out_msg_pos.data_pos >= trail_off;

		if (!in_trail)

			total_max_write = trail_off - con->out_msg_pos.data_pos;



		if (in_trail) {

			total_max_write = data_len - con->out_msg_pos.data_pos;



			page = list_first_entry(&msg->trail->head,
@@ -990,14 +993,13 @@ static int write_partial_msg_pages(struct ceph_connection *con) 


		if (do_datacrc && !con->out_msg_pos.did_page_crc) {

			void *base;

			u32 crc;

			u32 tmpcrc = le32_to_cpu(msg->footer.data_crc);

			u32 crc = le32_to_cpu(msg->footer.data_crc);

			char *kaddr;



			kaddr = kmap(page);

			BUG_ON(kaddr == NULL);

			base = kaddr + con->out_msg_pos.page_pos + bio_offset;

			crc = crc32c(tmpcrc, base, len);

			crc = crc32c(crc, base, len);

			msg->footer.data_crc = cpu_to_le32(crc);

			con->out_msg_pos.did_page_crc = true;

		}
@@ -1702,9 +1704,6 @@ static int read_partial_message_bio(struct ceph_connection *con, 
	void *p;

	int ret, left;



	if (IS_ERR(bv))

		return PTR_ERR(bv);



	left = min((int)(data_len - con->in_msg_pos.data_pos),

		   (int)(bv->bv_len - con->in_msg_pos.page_pos));